As Internet Protocol (IP) technologies for configuring an L2VPN, EtherIP (see RFC3378), and L2TPv3 (see RFC3931) are standardized by the IETF. In the case of EtherIP, VPN equipment catches an ether frame flowing on a connected LAN, encapsulates the ether frame with an EtherIP header and an IP header, and sends the ether frame to opposite VPN equipment. The VPN equipment receives an IP packet including the ether frame encapsulated with the EtherIP header and IP header, and takes out the ether frame from the received IP packet. Then the VPN equipment having received the IP packet sends the ether frame to the connected LAN. Thus an L2VPN is configured. L2TPv3 defines two logical communication channels (control channel and data channel). The control channel establishes and releases the control connection and session. The data channel transfers the ether frame by using the established session. The ether frame is transferred using an L2TP session header. The session header is encapsulated with an IP or UDP/IP header.